A team of researchers led by Professors Lih-Juann Chen and Chien-Neng Liao has endeavored in the research of advanced materials at an atomic scale using in situ ultra high vacuum transmission electron microscope. One of their foci is to explore the movement of Cu atoms in super fine copper line in integrated circuit under high density current. The team has discovered that Cu atom diffusion along grain boundary is affected by the structure of nano bi-crystal and shows signs of slow-down. This new discovery was proudly reported in the August 22^nd issue of Science.

Grain boundary is a common structure in materials that can influence mechanical strength and properties such as electricity, magnetism, light and heat. Atomic diffusion along grain boundary can cause micro-structural change in materials and therefore affect the properties of materials. Although atomic diffusion along grain boundary has long been a known fact, no one has directly observed the phenomenon or further changed the phenomenon by controlling the structure of grain boundary. NTHU research team installed one of the world's ten state-of-the-art in situ UHV-TEMs that became a powerful tool for them to study the structural and dynamic mechanism of materials at an atomic scale. Using the in situ UHV-TEM, the team successfully observed the migratory behavior of Cu atoms on crystal surface and along grain boundary under high density current. The most exciting discovery was that inside the crystal electron, Cu atom migration can be effectively slowed in the contact area of nano bi-crystal structure and grain boundary. This means that high density nano bi-crystal structure can be introduced into the copper line of integrated circuit chip to effectively resolve the inactivity of micro-electronic device caused by electromigration. The important discovery marks an enormous stride forward for the next generation of integrated circuit production technology development.